1. Field of the Invention
The present invention relates to a printing apparatus and control method thereof and, more particularly, to a printing apparatus including a full-line head and a control method thereof.
2. Description of the Related Art
Recently, inkjet printing apparatuses are becoming popular as printing apparatuses which implement high-quality color printing at low cost. As a recent trend, inkjet printing apparatuses adopt a structure using a head cartridge which is configured by integrating, with a printhead, an ink tank storing ink and is exchangeable from the printing apparatus main body. The head cartridge can advantageously reduce the cost by shortening the channel extending from the printhead to the ink tank, and reduce the ink consumption amount in suction recovery. For commercial use, a printing apparatus including a full-line head having a printhead printing width almost equal to the paper width is also available. Such an apparatus is used in a long term because an exchangeable full-line head can greatly prolong the service life.
Further, as a recent trend of printing apparatuses, the number of print elements of the printhead is increased to integrate the print elements at high density in order to meet a demand for higher image qualities. A high-resolution image can be printed by increasing the number of print elements and the resolution.
However, as the number of print elements increases, the printhead temperature rises more greatly owing to heat generated by the print elements. If the chip temperature of the printhead becomes high, the physical properties of discharge ink change. As a result, the ink amount per discharged ink droplet changes, changing the color appearance and degrading the printing quality. To avoid this, it is a common practice to arrange a temperature sensor in the printhead, adjust a driving pulse to be input to the printhead based on an output result from the temperature sensor, and stabilize the color appearance of a printed image. To implement this technique, the accuracy of printhead temperature detection is very important.
However, if a high-accuracy temperature sensor is arranged in a printhead which is handled as consumables on the premise of replacement, the cost of the printhead itself rises. To solve this problem, there has conventionally been proposed a technique of arranging a high-accuracy sensor in a printing apparatus main body and fitting the temperature sensor of a printhead in the sensor of the printing apparatus main body, instead of improving the accuracy of the temperature sensor in the printhead (see Japanese Patent Laid-Open No. 7-209031).
However, the technique disclosed in Japanese Patent Laid-Open No. 7-209031 assumes that the printing apparatus main body incorporates a high-accuracy sensor, so the cost of the printing apparatus main body rises.
In addition, the temperature is most likely to differ between the sensor inside the printing apparatus main body and the vicinity of the printhead, and the sensor arrangement position and fit-in sequence become complicated.